Driving device for bicycle

Abstract

The invention relates to a drive device for a bicycle, wherein the drive device has a pawl flywheel mechanism (14). The pawl flywheel mechanism (14) has a first ring (20) with pawls (24) movably supported thereon and a second ring (22) with a tooth arrangement (26). Furthermore, the drive device has at least one sensor device which is designed to detect a deformation of the first ring (20) of the pawl flywheel mechanism (14) on the basis of the applied drive force. The sensor device (24) has an associated deformation sensor (28) for each pawl (24) in each case. The invention further relates to a method and to a bicycle.

Description

Technical Field

[0001] The invention relates to a drive device for a bicycle. The invention also relates to a method for operating a drive device for a bicycle and to a bicycle. Background Art

[0002] In bicycles, it is known to provide a flywheel mechanism. Thus, for example, the pedal shaft can be decoupled from the driven running wheel. Thus, the bicycle can travel without the corresponding pedal of the bicycle rotating. In electric assisted vehicles, for example, a flywheel mechanism is used, and the drive motor can also be decoupled. However, in the blocked state, the flywheel mechanism can connect the two shafts to each other in a rotationally fixed manner, in order to achieve, for example, a transmission of driving force.

[0003] By detecting the deformation of the components of the flywheel mechanism, the transmitted driving force can be detected in this case, for example in order to control the drive. However, depending on the structure of the flywheel mechanism and the relative position of the two shafts connected to each other, interference variables may occur. For example, in the blocked state, radial forces can act on the flywheel mechanism which deform the flywheel mechanism regardless of the blocking state position. Depending on production tolerances and wear, the corresponding pawl of the flywheel mechanism can also engage differently with the toothing in the blocked state. Interference variables that do not directly correspond to the transmitted driving force can therefore also be caused. Therefore, the detected deformation may only correspond inexactly to the transmitted driving force.

[0004] DE 10 2012 100 682 A1 describes a torque sensor and a flywheel mechanism with a first rotating element, by means of which a torque to be determined can be transmitted in one rotational direction to a second rotating element coaxial with the first rotating element. Furthermore, a device is described for establishing a rotation of the first rotating element relative to the second rotating element in the rotational direction and for determining the torque relative to the established rotation. The torque determination is therefore very complex. Summary of the invention

[0005] A first aspect relates to a drive device for a bicycle. The drive device may, for example, have a gear mechanism, a pedal shaft, a running wheel and corresponding force transmission elements to the running wheel. The drive device may have a drive motor, for example in the form of an electric motor. The drive device may be configured for a bicycle in the form of an electric power-assisted bicycle. The drive device may be configured to transmit a driving force from a cyclist and optionally from a drive motor to the running wheel.

[0006] The drive device has a ratchet flywheel mechanism. The ratchet flywheel mechanism is also called a blocking ratchet flywheel mechanism. The flywheel mechanism can, for example, transmit torque in only one direction of rotation, wherein the flywheel mechanism is then in its blocking state. However, in the case of a relative reversal of the direction of rotation, the connection is released independently in the opposite direction, whereby the flywheel mechanism is then in its released state. In the blocked state, the corresponding ratchet of the ratchet flywheel mechanism can engage. However, in the released state, the ratchet of the ratchet flywheel mechanism, for example, slides out. The ratchet flywheel mechanism can, for example, be configured to uncouple a drive such as a pedal shaft from an output member. For example, the ratchet flywheel mechanism can also uncouple the pedal shaft from the drive motor or uncouple the drive motor from the pedal shaft. The ratchet flywheel mechanism can also be configured to change the gears in the gear mechanism of the drive device.

[0007] The pawl freewheel mechanism has at least a first ring and a second ring. Both rings can in each case be permanently connected to the shaft of the drive device in a rotationally fixed manner. The rings can also form a disk. For example, a ring in the form of an inner ring with radially extending walls can be connected to the shaft in a rotationally fixed manner. The rings can also have non-annular partial areas, recesses and alternatively or additionally dispersed through-openings.

[0008] The second ring has a tooth arrangement. The tooth arrangement can extend, for example, radially along the circumference of the second ring, either at the inside or at the outside. The tooth arrangement can be configured for engagement via a pawl. The tooth arrangement can have tooth tips protruding in the direction of the first ring and valleys between the tooth tips.

[0009] The pawl freewheel mechanism has a pawl movably supported on the first ring. The pawl freewheel mechanism may have a large number of these pawls, for example two, three, four or more pawls. As a result of more pawls, higher torques may be transmitted. The pawl may also be referred to as a locking pawl. The pawl may, for example, be pivotally supported on the first ring around an associated axial rotation axis at one end facing the second ring in each case. The pawl is, for example, in a blocking state of the pawl freewheel mechanism engaged with the toothing of the second ring. The pawl may, for example, be elastically pretensioned with respect to this engagement. In the released state, the engagement of the pawl with the toothing is cancelled. In the blocked state, the two rings are connected to each other in a rotationally fixed manner by means of engagement. In the released state, the pawl, for example, slides off on the toothing, and the two rings can rotate relative to each other in one rotational direction. The pawl may, for example, enable the two rings to rotate relative to each other in one rotational direction, and prevent the pawl from engaging with the toothing in the opposite rotational direction. The pawl and the toothing may be arranged at the mutually facing sides of the two rings.

[0010] The two rings can be arranged coaxially relative to each other. The two rings can be arranged in the same axial region. In each case, the two rings can be supported rotatably around a central axis. For example, one of the two rings is permanently connected to an input shaft of the pawl freewheel mechanism or to a shaft of the drive device in a rotationally fixed manner. For example, the other of the two rings is permanently connected to an output shaft of the pawl freewheel mechanism or to a shaft of the drive device in a rotationally fixed manner.

[0011] The drive device has a sensor device, which is configured to detect the deformation of the first ring of the pawl freewheel mechanism based on the applied driving force. The driving force can be transmitted to the second ring, for example, in a blocked state, or from the second ring to the first ring, in a blocked state. The driving force can be introduced into the drive device, for example, by the rider of the bicycle at the corresponding pedal. Additionally or alternatively, the driving force can be introduced into the drive device by the drive motor. The detected deformation can, for example, allow statements about the torque transmitted. The applied driving force can correspond to the transmitted torque. As a result of the detection, for example, power measurement, automatic control of the shifting of the bicycle, and control of the drive motor according to the driving force applied to the pawl freewheel mechanism, alternatively or additionally, may be feasible. Control can also be performed directly according to the detected deformation. Additional functions can also be based on this detection, such as determining the wear of the pawl freewheel mechanism.

[0012] In each case, the sensor device has an associated deformation sensor for each pawl. Each deformation sensor is, for example, configured to detect deformation in a measurement area, for example beside or on the associated pawl. As a result of providing a deformation sensor for each pawl, a deformation of the first ring on each pawl can be detected. Therefore, a separate statement about the driving force transmitted by each pawl is possible. Therefore, a statement about each pawl involving the torque transmitted at this position is also possible. The sensor device can be configured to separately detect the driving force transmitted at each pawl. For example, as a result of the relevant deformation measurement of each pawl, the shape tolerances of the shaft, the tooth device and the pawl or the tolerances of the concentricity of the components of the drive device can be compensated so that the corresponding operating variables can be measured in a particularly accurate manner. Such tolerances and corresponding individual deviations in the individual drive devices as a result of production tolerances and assembly tolerances may lead to uneven engagement of the pawl with the tooth device. Therefore, the pawl can transmit different amounts of force and is also loaded to different degrees. Even without tolerance deviations, the loads that prevail in the drive device may also deform the components, and the pawl may therefore be loaded to different degrees. These deviations, which together with each detent may also deform the first ring to different degrees, may also depend on the relative rotational position of the two rings with respect to each other.

[0013] However, as a result of providing a deformation sensor for each pawl, the sensor device can partially or even completely compensate for these influences. The sensor device can, for example, be configured to detect how much load each pawl transmits. The deformation sensor can generate an associated measurement value for each individual pawl. Thus, new evaluation possibilities are also provided, which will be explained below.

[0014] The deformation sensors can be fixed to the first ring. The deformation sensors can be arranged spaced apart from each other in a uniform manner in the circumferential direction. The deformation sensors can be arranged on the first ring in a uniform range or at a uniform radial spacing relative to the axis of rotation. The deformation sensors can be arranged axially, for example, at the height of the pawl freewheel mechanism. The sensor device can be configured, for example, to determine the deformation in a resistive, magnetic, optical or acoustic manner. For example, the sensor device can have a plurality of wire strain gauges fixed to the first ring as deformation sensors. Alternatively, for example, Hall sensors can also be used. The sensor device can have an evaluation device to evaluate the corresponding sensor signals. The pawls can be spaced apart from each other in a uniform manner in the circumferential direction. The pawls can be arranged symmetrically on the first ring, for example. The deformation sensors can be arranged symmetrically on the first ring. All deformation sensors can be arranged identically relative to the associated pawls. For example, each deformation sensor can have the same radial spacing and the same spacing in the circumferential direction relative to its associated pawl.

[0015] The first ring is connected to the pedal shaft, for example in a rotationally fixed manner. For example, the first ring and the pedal shaft can be constructed in an integral manner. The sensor device can be configured to detect a bending of the first ring and alternatively or additionally a bending of the pedal shaft. Thus, the deformation sensor can detect a bending of the pedal shaft during operation of the drive device.

[0016] The second ring can have a continuous toothing in the circumferential direction. This makes it possible to ensure engagement in a particularly fast manner and, for example, even at a small rotation angle in the blocking direction. In addition, the second ring can thus be easily produced. For example, the toothing can be formed by means of the cover surface of the second ring. The toothing can, for example, be arranged radially on the inside or radially on the outside.

[0017] In one embodiment of the drive device, a first ring in the form of an inner ring and a second ring in the form of an outer ring can be provided. The second ring can be arranged radially on the outside relative to the first ring. The tooth arrangement can then be arranged radially on the inside on the second ring. Production can then be particularly cost-effective and simple. In addition, the corresponding sensor can thus be fitted to the first ring in a simple manner. The corresponding pawl can, for example, be supported on the first ring radially on the outside.

[0018] In one embodiment of the drive device, it can be provided that the first ring is in the form of an outer ring and the second ring is in the form of an inner ring. The second ring can be arranged radially on the inside relative to the first ring. The tooth arrangement can then be arranged radially on the outside on the second ring. The corresponding pawl can be supported on the first ring, for example, radially on the inside. The assembly of the pawl can thereby be simplified.

[0019] In one embodiment of the drive device, it can be provided that each deformation sensor is arranged adjacent to the associated pawl on the first ring. For example, each deformation sensor can be arranged in the same circumferential area and, alternatively or additionally, has the same radial spacing from the axis of rotation as the associated pawl. The circumferential area can be defined, for example, between the axis of rotation and the opposite ends of the pawl or the recess in which the pawl is arranged in the circumferential direction. The deformation sensor can also be arranged radially on the inside or radially on the outside relative to the pawl. In the case of an adjacent arrangement, the measuring area of ​​the sensor can be positioned as close as possible to the associated pawl or even on the associated pawl. The deformation sensor can also be offset in the circumferential direction relative to the associated pawl and alternatively or additionally arranged in the radial direction.

[0020] In one embodiment of the drive device, provision can be made that the first ring has a recess in the circumferential region between adjacent pawls in each case. Alternatively or additionally, the first ring can have a recess in the circumferential region between adjacent deformation sensors in each case. For example, between adjacent pawls, a free space can be provided in the circumferential direction at least with the same radial spacing as the pawls relative to the axis of rotation. As a result of the recess, force paths between different pawls can be avoided, and therefore also force paths between their associated deformation sensors. Thus, the influence of other pawls and the forces transmitted to one pawl at this position can be reduced or even completely prevented. Thus, each deformation sensor can detect a deformation corresponding to the force applied at the associated pawl in a particularly precise manner. As a result of the spatial separation based on the respective recess, the respective pawl load can therefore be detected in a particularly precise manner, without the detection being influenced by the loads of the other pawls.

[0021] In one embodiment of the drive device, it can be provided that each deformation sensor is arranged on the first ring in the circumferential direction behind the associated pawl in the direction of the force acting on the first ring from the corresponding pawl. The pawl can, for example, have a first end that engages with the toothing device in the blocked state of the pawl freewheel mechanism. The pawl can have, for example, a second end opposite to the first end. The second end is supported on the first ring, for example in the associated recess, for example, in the blocked state. The second end can be rotatably supported on the first ring. The vector pointing from the first end to the second end can correspond to the direction of the force acting on the first ring from the corresponding pawl. The circumferential direction portion of the vector can correspond to the direction in which each deformation sensor is arranged behind the associated pawl. The measuring area can therefore be particularly well located in the force transmission path, and the detected deformation can therefore be a particularly advantageous measured variable.

[0022] In one embodiment of the drive device, it can be provided that at least one pawl is in the form of a double pawl. For example, all pawls can be in the form of a double pawl. The double pawl can, for example, have two separate pawl elements. For example, the double pawl can also have two top ends, which are positioned in the circumferential direction as follows: one top end is behind the other top end. Such a pawl can engage at more than one position and, for example, transfer loads at two positions. The pawl elements can, for example, all engage with the tooth device in the blocked state of the pawl flywheel. The two pawl elements can be arranged one behind the other in the axial direction, but in the same circumferential area and in the same radial area. The double pawl can be constructed in an integral manner and, for example, have two engagement areas. The double pawl can have the same axis of rotation for each pawl element, alternatively or additionally having a common recess. The two pawl elements can use the same bearing on the first ring. For each double pawl, only one associated deformation sensor can be provided. A deformation sensor for each double pawl can also be arranged axially on both sides of the first ring. For each pawl element, an associated deformation sensor can also be provided. As a result of the double pawl, the pawl freewheel mechanism can be cost-effective and compact and still transmit high loads. It is also possible to provide three pawls or a pawl with more than three pawl elements. The above statements related to the double pawl apply in this case in an analogous manner. A normal pawl can, for example, have only one pawl element. For example, all pawls can be in the form of normal pawls.

[0023] In one embodiment of the drive device, provision can be made for the drive device to have an evaluation device which is designed to evaluate the deformation of the first ring as detected by the deformation sensor. The evaluation device can have a microprocessor. As a result of the evaluation, for example, the force normally applied can be calculated. As a result of the evaluation, the load applied to each individual pawl can also be calculated. The evaluation can be performed, for example, by means of a table comparison, an analytical calculation or a previously trained neural network. For example, as a result of the evaluation, a disturbance variable can also be calculated.

[0024] In one embodiment of the drive device, provision can be made for the evaluation device to be constructed to determine the pedaling behavior of the rider as a function of the deformation of the first ring as detected by the deformation sensor. The pedaling behavior may, for example, have a pedaling frequency. The pedaling behavior may have a driving force introduced over time. The pedaling behavior may have an item of information about whether the rider is standing or sitting when pedaling. For example, it can be recognized whether the rider pedals while standing or sitting, since in this case the load and therefore the deformation of the pedal shaft changes. The pedaling behavior can, for example, be indicated or used to control the drive motor. As a result of the deformation detected in the area of ​​each pawl, a bending of the pedal shaft and an introduced torque can be recognized.

[0025] For example, a non-circular pedaling action can be identified and a notification or correction suggestion can be given to the rider. The rider's ability can be optimized thereby. Therefore, medical problems caused by bicycle riding can also be prevented. For example, the support level of the drive motor can be adapted according to the determined pedaling behavior. The type of support within the rotation depending on the determined pedaling behavior can also be controlled. For example, when pedaling, the drive motor can be controlled to compensate for the dead point. As a result of the dead point compensation, when the corresponding pedal is completely at the top and completely at the bottom and the rider can then, for example, not introduce any torque, an additional driving force can be provided by the drive motor. Control and output can be performed by means of an evaluation device. For output, an output device can also be provided. This can, for example, have a screen and transmit corresponding data, for example, to a smart phone, alternatively or additionally. For control, a control device for controlling the drive motor can also be provided. The control device can, for example, have an inverter that controls the power supply of the drive motor in the form of an electric motor.

[0026] In one embodiment of the drive device, provision can be made for the evaluation device to be configured to determine the engagement behavior of the pawl freewheel mechanism as a function of the deformation of the first ring as detected by the deformation sensor. The engagement behavior can, for example, contain information about how far each pawl engages with the tooth arrangement and, optionally or additionally, how well. The engagement behavior can have an associated drive force transmitted via each pawl.

[0027] Thus, errors in the pawl-freewheel mechanism can be identified. For example, the pawl, the tooth arrangement or the first ring with the recess may be subject to tolerances in their shape. The corresponding components may also not be completely concentric or parallel. This may be the result of production errors or assembly errors and the wear of the components until the defect. When the pawl does not always transmit the same amount of force relative to each other depending on the engagement position of the pawl-freewheel mechanism, this can be identified by the evaluation device. These information items can form part of the determined engagement behavior. With respect to the determined engagement behavior, the corresponding deformation signal can be corrected, and alternatively or additionally, interference variables can be compensated, and the applied torque can therefore be established very accurately. Using information related to production or assembly errors, for example, the manufacturer can also perform quality control on the production line. As part of the determined engagement behavior, the evaluation device can identify errors in production and assembly with the help of deformation sensors associated with the pawl. For example, in the context of so-called predictive maintenance, using information related to wear and defects, maintenance operations until replacement can be further planned.

[0028] In one embodiment of the drive device, it can be provided that the evaluation device is configured to identify the damaged teeth of the tooth device of the second ring based on the engagement behavior. Alternatively or additionally, the evaluation device can be configured to identify the damaged pawl based on the engagement behavior. The drive device can have a drive motor and a control device. The control device can be configured to control the drive motor so as to avoid the pawl from engaging with the teeth that have been identified as damaged. For example, in the case where the pawl is engaged with the tooth device, or when the pawl freewheel mechanism becomes a blocking state, it can be identified whether the pawl is engaged with one or more damaged teeth. By driving with the drive motor, the engagement position can then be changed, for example, temporarily changed to a released state. Alternatively or additionally, the position of the damaged tooth can be stored, and in principle, it can be prevented from becoming a blocking state at such a position, for example, by means of a corresponding control of the drive motor. In this case, a position sensor can be provided for the relative position of the two rings. As a result of the limited number of teeth of the tooth device, there are a limited number of engagement positions. Over a relatively long period of time, the corresponding measured values ​​of the engagement behavior can be stored and compared. If the tooth is subsequently damaged, this can be identified with reference to the corresponding loading behavior of the pawl known during the period of time. In this case, for example, the drive motor can briefly accelerate one ring beyond the rider's crank speed. As a result, the pawl freewheel mechanism is briefly disengaged. As soon as the speed of the drive motor is adjusted to the speed of the pedal shaft again, the pawl freewheel mechanism is changed to the blocking state again. As a result of this control, the engagement position in which the damaged tooth no longer engages with the pawl can be shifted. Thus, complete failure and resulting damage can be avoided. As a result, the pawl freewheel mechanism can have a longer service life.

[0029] A second aspect relates to a method for operating a drive device according to the first aspect. The corresponding advantages and further features can be derived from the description of the first aspect, wherein embodiments of the first aspect also form embodiments of the second aspect and vice versa. The method has the step of detecting, for each pawl, a deformation of a first ring of a pawl freewheel mechanism with an associated deformation sensor. The method additionally has the step of evaluating the detected deformation of the first ring. For example, the applied drive force or the transmitted torque can be determined with the aid of the evaluation. The engagement behavior and, alternatively or additionally, the pedaling behavior can also be determined.

[0030] In one embodiment of the method, it may be provided that the determination of the pedaling behavior of the rider is performed according to the deformation of the detected first ring. In addition, the method may have a step of outputting the determined pedaling behavior to the rider. The rider can thereby control his / her pedaling behavior. For example, a graph of the driving force introduced by him / her over time may be shown to the rider. Alternatively or additionally, the determination of the suggested changes to the pedaling behavior and the output of these suggested changes to the rider may be performed. For example, a prompt for a more circular pedaling action and a more effective use of the bicycle may be given to the rider. Alternatively or additionally, the control of the drive motor of the drive device may be performed according to the determined pedaling behavior. For example, a change of the support platform may be performed, or the support driving force within the rotation of the pedal shaft may be changed, for example, in order to compensate for a dead point. In this case, the control of the drive motor of the drive device depending on the determined pedaling behavior may be superimposed on the control of the drive motor depending on the determined applied driving force or the determined transmitted torque, for example, by shifting the control characteristic line.

[0031] In one embodiment of the method, it may be provided that the determination of the engagement behavior of the pawl flywheel mechanism is performed according to the detected deformation of the first ring. In addition, the method may have a step of determining the torque transmitted by the pawl flywheel mechanism according to the determined engagement behavior. For example, the detected deformation value may be modified according to the determined engagement behavior, and the torque transmitted by the pawl flywheel mechanism may be determined based on the modified deformation value. Alternatively or additionally, the determination of the assembly error in the pawl flywheel mechanism may be performed according to the determined engagement behavior. Alternatively or additionally, the production error in the pawl flywheel mechanism may be determined according to the determined engagement behavior. Production errors and assembly errors may be indicated for quality control, for example, as a general error message or also with information items related to the type of error that is particularly present. Alternatively or additionally, the maintenance prediction of the pawl flywheel mechanism may be determined according to the determined engagement behavior. For example, it is possible to calculate when the second ring or the pawl flywheel mechanism of the pawl flywheel mechanism is generally intended to be replaced. The prediction may be output, for example, as the remaining time of use or the remaining operating power. Alternatively or additionally, a defective tooth of the toothing of the second ring may be identified and a drive motor of the drive device may be controlled in order to prevent the pawl from engaging with a tooth that has been identified as defective.

[0032] A third aspect relates to a bicycle having: a drive device according to the first aspect; and an output element. The output element may, for example, be a rear running wheel of the bicycle. For example, when the pawl freewheel mechanism is in its blocked state, the output element may be drivable by the drive device. The drive device may be operated with a method according to the second aspect. The corresponding advantages and other features may be derived from the description of the first or second aspect, wherein embodiments of the first and second aspects also form embodiments of the third aspect, and vice versa. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The invention shows the installation of a driving device with a ratchet freewheel mechanism in a bicycle.

[0034] Figure 2 Shown according to Figure 1 A first embodiment of a pawl freewheel mechanism of a drive device, as a schematic side view along the rotation axis of the pawl freewheel mechanism.

[0035] Figure 3 Shown according to Figure 1 A second embodiment of a pawl freewheel mechanism of a drive device, as a schematic side view along the rotation axis of the pawl freewheel mechanism.

[0036] Figure 4 Shown according to Figure 3 A pawl freewheel mechanism as a schematic perspective view.

[0037] Figure 5 shows the operation according to Figure 1 Method of driving the device. DETAILED DESCRIPTION

[0038] Figure 1 The installation of a drive device in a bicycle is schematically shown. The drive device has a pedal shaft 10 with pedal arms 12, which are fixed to the pedal shaft 10 on both sides in a rotationally fixed manner. A pedal, not shown, is in each case rotatably fixed to the pedal arm 12. The drive device also has a ratchet freewheel mechanism 14 and an output shaft 16 with a pinion. The ratchet freewheel mechanism 14 can be independently changed between a blocking state, in which the ratchet freewheel mechanism 14 connects the pedal shaft 10 to the output shaft 16 in a rotationally fixed manner, and a release state, in which the pedal shaft 10 can rotate relative to the output shaft 16 (depending on the relative rotation direction of the pedal shaft 10 and the output shaft 16 relative to each other). In the blocking state, a torque can be transmitted accordingly by the ratchet freewheel mechanism 14.

[0039] The drive device has a sensor device which is designed to detect deformations of components of the ratchet freewheel mechanism 14. Based on this deformation, the drive force introduced by the rider at the pedal shaft 10 is determined.

[0040] The first embodiment of the ratchet flywheel mechanism 14 is Figure 2 is shown as a schematic side view. The pawl freewheel mechanism 14 has a first ring 20 in the form of an inner ring. The first ring 20 forms a disk, which is permanently connected to the pedal shaft 10 in a rotationally fixed manner. A second ring 22 is arranged coaxially with respect to the first ring 20 and radially at the outside. The second ring 22 is permanently connected to the output shaft 16 in a rotationally fixed manner. On the first ring 20, radially on the outside, four pawls 24 are movably supported. The second ring 22 has a toothing 26 extending radially on the inside and facing the pawls 24. The toothing 26 is configured for engagement with the pawls 24. Figure 2 The pawl freewheel mechanism 14 is shown in a blocked state in which the pawl 24 is engaged with the tooth arrangement 26. Thus, as a result of the driving force acting on the foot pedal 10, torque can be transmitted from the first ring 20 to the second ring 22.

[0041] also, Figure 2Four deformation sensors 28 of the sensor arrangement are shown. One pawl 24 is associated with each deformation sensor 28. The deformation sensors 28 are adhesively bonded to the first ring 20 at the end face and are in the form of wire strain gauges. Each deformation sensor 28 is arranged radially on the inside with respect to the associated pawl 24 and is arranged adjacent to the associated pawl 24 in the same circumferential region as the associated pawl 24. The sensor arrangement thus detects isolated measured values ​​of the deformation for each individual pawl 24, from which measured values ​​it is possible to infer how much load is applied to this pawl 24 in each case. Disturbance variables caused, for example, by reaction forces on the pawl 24 and bending of the pedal shaft 10 under load can thereby be calculated and the actually applied drive force can be determined in a very precise manner.

[0042] Figure 3 A second embodiment of a pawl freewheel mechanism 14 is shown. Only the differences with respect to the first embodiment will be described below. In the second embodiment, the first ring 20 has recesses 30 in each case in the circumferential region between adjacent pawls 24. These recesses 30 are in the form of wedge-shaped free spaces protruding radially inwards, on which the disk of the first ring 20 is interrupted. In other embodiments, the recesses 30 are formed in a different way. As a result of the recesses 30, the regions of the first ring 20 to which the deformation sensors 28 are fixed are in each case spatially separated from one another in the circumferential direction. Therefore, in each case, the deformation and therefore the deformation measurement performed adjacent to each pawl 24 by means of the associated deformation sensor 28 is not influenced by the pawl load on the remaining pawls 24 or at least to a lesser extent by the pawl load on the remaining pawls 24.

[0043] In the second embodiment, the deformation sensors 28 are no longer arranged in each case in the same circumferential region as the associated pawl 24. Instead, each deformation sensor 28 is arranged on the first ring 20 in the circumferential direction behind the associated pawl 24 in the direction of the forces acting on the first ring 20 from the respective pawl 24. In this case, the direction is generated by means of the circumferential portion of a vector extending from the end of each pawl 24 engaging with the toothing 26 to the end of each pawl 24 resting on the first ring 20 and rotatably supported thereon.

[0044] In the first embodiment, the pawl 24 is in the form of a single pawl, that is, has one pawl element. Figure 4 In the schematic perspective view of the second embodiment in FIG. 1 , it can be seen that the pawl 24 of the second embodiment of the pawl freewheel mechanism 14 has a central gap extending in the circumferential direction. An annular spring is arranged in the gap, which presses all the pawl elements 32 together and engages.

[0045] Figure 5 A method for operating a drive device is shown. In a first step 40, for each pawl 24, the deformation of the first ring 20 of the pawl freewheel mechanism 14 is detected using the associated deformation sensor 28. In a second step 42, the detected deformation of the first ring 20 is evaluated. In one embodiment of the method, the driving force applied to the pawl freewheel mechanism 14 is established thereby. In another embodiment of the method, alternatively or additionally, the pedaling behavior of the rider is established based on the detected deformation of the first ring 20. The pedaling behavior is output to the rider. Alternatively or additionally, change suggestions for the pedaling behavior are determined and output to the rider. Alternatively or additionally, the control of the drive motor of the drive device is performed based on the determined pedaling behavior. In another embodiment of the method, alternatively or additionally, the engagement behavior of the pawl freewheel mechanism 14 is determined based on the detected deformation of the first ring 20. Based on the engagement behavior, assembly errors and production errors are determined and output. Alternatively or additionally, a maintenance prediction of the pawl freewheel mechanism 14 is generated based on the determined engagement behavior. Alternatively or additionally, a defective tooth of the toothing 26 of the second ring 22 is identified and the drive motor of the drive device, if present, is controlled in order to prevent the pawl 24 from engaging the tooth identified as defective.

[0046] List of reference numerals

[0047] 10 Pedal shaft

[0048] 12 Foot pedal arm

[0049] 14 Pawl flywheel mechanism

[0050] 16 Output shaft

[0051] 20 First Ring

[0052] 22 Second Ring

[0053] 24 Pawl

[0054] 26 teeth device

[0055] 28 Deformation Sensor

[0056] 30 concavity

[0057] 32 Pawl element

[0058] 40 Detection of deformation of the first ring

[0059] 42 Evaluate the deformation of the first ring detected.

Claims

1. A drive device for a bicycle, wherein the drive device has a pawl freewheel mechanism (14), wherein the pawl freewheel mechanism (14) has a first ring (20) and a second ring (22), the first ring (20) having a pawl (24) movably supported on the first ring (30), the second ring (22) having a tooth device (26), and wherein the drive device has at least one sensor device, which is configured to detect a deformation of the first ring (20) of the ratchet freewheel mechanism (14) due to an applied drive force, The sensor device has in each case an associated deformation sensor (28) for each pawl (24).

2. A drive device according to any one of the preceding claims, characterized in that The first ring (20) is in the form of an inner ring and the second ring (22) is in the form of an outer ring.

3. The driving device according to claim 1, characterized in that: The first ring (20) is in the form of an outer ring and the second ring (22) is in the form of an inner ring.

4. A drive device according to any one of the preceding claims, characterized in that Each deformation sensor (28) is arranged on the first ring (20) adjacent to an associated pawl (24).

5. A drive device according to any one of the preceding claims, characterized in that The first ring (20) has recesses (30) in each case in the circumferential region between adjacent pawls (24).

6. A drive device according to any one of the preceding claims, characterized in that Each deformation sensor (28) is arranged on the first ring (20) in the circumferential direction behind the associated pawl (24) in the direction of the force acting on the first ring (20) from the corresponding pawl (24).

7. A drive device according to any one of the preceding claims, characterized in that The drive device has an evaluation device which is designed to evaluate a deformation of the first ring (20) as detected by the deformation sensor (28).

8. The driving device according to claim 8, characterized in that: The evaluation device is configured to determine a rider's pedaling behavior based on the deformation of the first ring (20) as detected by the deformation sensor (28).

9. The driving device according to claim 8 or 9, characterized in that: The evaluation device is configured to determine the engagement behavior of the ratchet freewheel mechanism (14) as a function of the deformation of the first ring (20) as detected by the deformation sensor (28).

10. The driving device according to claim 10, characterized in that: The evaluation device is designed to identify damaged teeth of the toothing (26) of the second ring (22) based on the engagement behavior, and the drive device has a drive motor and a control device, The control device is configured to control the drive motor so as to prevent the pawl (24) from engaging with a tooth that has been identified as damaged.

11. A method for operating a drive device according to any one of the preceding claims, wherein the method comprises the following steps: - for each pawl (24), detecting (40) a deformation of the first ring (20) of the pawl freewheel mechanism (14) with an associated deformation sensor (28); and - evaluating (42) the detected deformation of said first ring (20).

12. The method according to claim 12, wherein the method further comprises the following steps: - determining the rider's pedaling behavior based on the detected deformation of the first ring (20); as well as At least one of the following reaction steps: - outputting the determined pedaling behavior to the rider; - determining a suggested change to the pedaling behavior and outputting the suggested change to the rider; as well as - controlling a drive motor of the drive device as a function of the determined pedaling behavior.

13. The method according to claim 12 or 13, wherein the method further comprises the following steps: - determining the engagement behavior of the pawl freewheel mechanism (14) based on the detected deformation of the first ring (20); and At least one of the following reaction steps: - determining the torque transmitted by the pawl freewheel mechanism (14) based on the determined engagement behavior; - determining an assembly error in the pawl freewheel mechanism (14) based on the determined engagement behavior; - determining a production tolerance in the pawl freewheel mechanism (14) based on the determined engagement behavior; - generating a maintenance prediction of the pawl freewheel mechanism (14) based on the determined engagement behavior; and - identifying a damaged tooth of the toothing (26) of the second ring (22) and controlling the drive motor of the drive device to prevent the pawl (24) from engaging the tooth that has been identified as damaged.

14. A bicycle having: a drive device according to any one of the preceding claims; and an output element which can be driven by the drive device.

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